Xlubricants



Patented Apr. 19, 1938 STATES- PATENT OFFlCE Y LUBRICANTS ware No Drawing. Application .lune 9, 1934,

Serial No. 729,898

, Claims.

This invention relates to lubricants and more particularly to greases capable of withstanding high pressures.

An important object of the invention is to 5 prepare a grease having extreme pressure characteristics-and suitable for heavy duty roller bearing application. v v

The invention comprises broadly a rease having extreme pressure characteristics formed ,of a

soap and sulfurized mineral oil, the latter ob tained by heating free sulfur with a ,petroleum lubricating oil.

In compounding the lubricant a soap of a suitable mtal and a fatty material is made. Also,

a sulfurized mineral oil is prepared by heating free sulfur and a mineral oil, such as a heavy lubricating oil or cylinder stock. The soap and sulfurized oil are then mixed and formed into a grease of suitable consistency.

In the manufacture of greases in accordance with. the invention, we prefer to make a lime soap of a proper fatty material, although other soaps, such as sodium, aluminum, magnesium, mayalso. be used. A suitable lubricating oil is sulfurized and then the soap and sulfurized oil are mixed under proper conditions and in such proportions as to give the desired product. In preparing a grease for heavy duty roller bearings, for example, a lime soap of a good grade of tallow' is useful although other fatty oils orfatty.

acids, such as cottonseed oil, stearic acid, lard oil, and petroleum acids, such as naphthenic acids, may be used.

The mineral oil is sulfurized by treatment with free sulfurythe amount of sulfur being sufficient to incorporate about 0.75 to 1.5% therein, although larger amounts may be used if desired. The quantity of free sulfur necessary to obtain the desired amount in the oil will depend on the 40 method of incorporation. For an open grease kettle, about 3% will usuallybe sufficient and if a closed kettle is used wherein pressure is developed, the amount of sulfur may be reduced.

The proportionate amounts of lime soap and sulfurized oil may vary depending on the desired consistency of the resultant grease. For most purposes a product having an A. S. T. M. penetration of about 240-360 is suitable and there will be required for such .a product about 23-14% lime soap and 75-90% mineral oil. We prefer to use about 10-12% lime soap and about 80-85% sulfurized mineral oil in which case a product having a penetration of about 260-280 may be obtained. The following example will illustrate the preparation of one grease falling within the scope of the invention.

Per cent Tallow 11.3 Sulfurized oil 83.35 5 Lime 1.57 Water 3.78

and 3% of sulfur and heating the same in a kettle m for about 5 hours at 400 F. The tests on the original-and finished product were as follows:

Unsulfurized Sulfurpale oil ized oil 15 Sulfur per cent" 0.35 1.4 Visc., Saybolt universal at 210 F 90 112 Extreme pressure test pounds 5 25 20 The grease was prepared by charging the A tallow, lime, about 5-10% of the sulfurized oil, and about of the water into a steam jacketed grease kettle provided with the usual paddle stirrers and operated under pressure. The tem- 25 perature was brought to about 300 F. in about an hour and was maintained at 300-325 F. for about one and one-halfhours with the pressure being from 40 to pounds. The mixture was then charged into an open top steam jacketed 30 kettle, heated to about 280 F. until foaming had subsided, and more of the sulfurized oil was added.

When the temperature had fallen below 200 F.

the remainder of the water was added until the product was satisfactorily emulsified, resulting in a very smooth, buttery grease. After stirring to the desired consistency the product was drawn out. The product testzd as follows:

Ordinary lime soap greases show extreme pressure tests of only 5 or 10 lbs. whereas greases pre- 0 pared in accordance with the invention are capable of withstanding high pressures and are particularly useful for lubrication of heavy duty steel mill roller bearings.

The extreme pressure test referred to above 56 was made on a lubricant and wear tester manufactured by the Timken Roller Bearing Company.

Obviously many modifications and variations of the invention, as hereinbefore set forth. may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A solid, homogeneous lubricating grease having extreme pressure characteristics consisting mainly oi. about -85% oi a sulfurized hydrocarbon lubricating oil and 10-12% of a lime soap oia iatty material, said sulfurized oil resulting from the incorporation of a small proportion oi suiiur into the oil by a separate heat treatment of a mixture of the sulfur and the oil at about 400 F.

2. A homogeneous lubricating grease comprising at least about 80% of a sulfurized lubricating oil and a lime soap of a fatty material, said soap being present in sufiicient amount to render the grease solid, said suliurized lubricating oil consisting of a mineral lubricating oil reacted with a small proportion of sulfur under the influence 01' heat.

3. A homogeneous lubricating grease having extreme pressure characteristics comprising about 80-85% of a suliurized lubricating oil and a lime soap of a fatty material, said lime soap being present in suflicient amount to render the grease solid, said sullurized lubricating oil consisting essentially oi the reaction product resulting from heating a heavy hydrocarbon lubricating oil with a small proportion of free sulfur at a temperature in the region 01 400 F.

4. A solid homogeneous lubricating grease having extreme pressure characteristics consisting mainly oi a suifurized lubricating oil and 13-14% of a lime soap of tallow, said sulfurized lubricating oil consisting essentially of mineral lubricating oil suliurized by heat treatment at a temperature suiiicient to effect reaction between the oil and the sulfur.

5. A solid homogeneous lubricating grease having extreme pressure characteristics consisting mainly of a suliurized lubricating oil and 8-14% oi a lime soap of a fatty material, said sulfurized lubricating oil consisting essentially of a hydrocarbon lubricating oil reacted with sufllcient suliur at a temperature in the region of 400 F. to incorporate in the oil about OHS-1.5% sulfur.

GUS KAUFMAN. ROY F. NELSON. 

